ONCE upon a time, poet and novelist George Dawes Green decided to gather his friends in his apartment to share stories. When the casual event, dubbed “The Moth,” outgrew Green’s space, it moved to small clubs downtown, where creative types continued to tell true tales without notes.

Now, a dozen years and hundreds of stories later, The Moth is expanding to radio.

With public radio fans such as Garrison Keillor and Ira Glass of “This American Life,” “The Moth Radio Hour” will premiere its national program on Saturday in New York, beginning with five weekly episodes on WNYC.

“We discovered, through our CDs and podcasts, that audio is a really great way for people to have an intimate experience,” says Lea Thau, the executive director of the Moth. She notes that its weekly podcasts have been downloaded a total of 6.5 million times since 2008.

Stories will be culled from the various Moth entities, including the weekly NYC Story/Slam, more formal monthly Mainstage shows and community outreach programs, wherein veteran Moth-ites teach people how to tell a story.

“We go out of our way to find very different voices and to get stories from people you normally wouldn’t hear — not from people who’d write a book or you’d hear on NPR,” says Thau.

That said, you will hear from the professionals. Tune in and you might hear a disabled woman talk about falling in love with an “Italian Stallion” right next to a story by New Yorker writer Adam Gopnik, who reveals how he mistook the IM abbreviation LOL to mean “lots of love.”

“Storytelling, if it’s done well, looks easy and is done off the cuff, but that’s far from the truth,” says Thau.

At a recent Story/Slam at a packed Nuyorican Poets Cafe, host Dan Kennedy, author of the book “Rock On,” kept the night rolling, riffing on the stories and commenting about audience members’ best and worst meals, which had been scribbled on bits of paper. (The evening’s theme was food.)

He’s a lively host, but on the radio special, Kennedy just introduces the narrator and story. There’s no ad-libbing. “It’s pretty straightforward,” he says.

Thau hopes the radio show will eventually have some live specials and add some more “behind the scene stuff,” but for now, “the stories are the stars,” she says.

As popular as the show has become, it still maintains a certain intimacy, no matter the medium.

“What’s really cool is the event can get as big as it is, but the stories don’t seem to get affected,” says Kennedy.

“The popularity doesn’t affect the material. It comes down to this very simple thing of ‘This thing has happened to me, and I want to tell you about it.’ “

“The Moth Radio Hour” can be heard on WNYC on Saturdays at 4 p.m. on 93.9 FM and Sundays at 10 p.m. on AM 820. For more information, visit themoth.org.